Nucleotide sequence encoding carbamoyl phosphate synthetase II

ABSTRACT

The present invention provides a nucleotide sequence encoding carbamoyl phosphate synthetase II of Plasmodium falciparum. Carbamoyl phosphate synthetase II catalyses the first committed and rate-limiting step in the de novo pyrimidine biosynthetic pathway. P. falciparum relies exclusively on pyrimidine synthesis de novo because of its inability to salvage pyrimidines. Mature human red blood cells, however, have no recognised requirement for a pyrimidine nucleotide. Accordingly, this enzyme represents a prime chemotherapeutic locus. The present invention relates to the use of the sequence encoding carbamoyl phosphate synthetase II in the recombinant production of carbamoyl phosphate synthetase II and to antisense molecules, ribozymes and other gene inactivation agents designed from this sequence.

This is a national phase filing of PCT application PCT/AU93/00617, filedDec. 2, 1993.

The present invention relates to nucleotide sequences encoding carbamoylphosphate synthetase II of Plasmodium falciparum, to methods ofproducing this enzyme using recombinant DNA technology and to the use ofthis sequence and enzyme in the design of therapeutics.

BACKGROUND OF THE INVENTION

The urgency for the design of novel chemotherapeutic agents for thetreatment of malaria has been renewed in recent times due to theevolution of human malarial parasites, primarily Plasmodium falciparum,which are resistant to traditional drugs. Research into a vaccine seemsa very plausible alternative, but after years of investigation, noclinically acceptable product has come to date. At the same time, thereis also an increasing decline in the efficacy of insecticides againstmosquito vectors. At present, more than two-thirds of the world'spopulation--approximately 500 million people--are thought to live inmalaria areas (Miller, 1989). It ranks eighth in the World HealthOrganization's (WHO) list of ten most prevalent diseases of the world(270 million infections a year) and ranks ninth of the ten most deadlydiseases, claiming over 2 million lives a year (Cox, 1991; Marshall,1991). Though chiefly confined to poor nations, there are recent reportsof infections in the United States (Marshall, 1991) and Australia(Johnson, 1991), and ever increasing cases of travellers' malaria(Steffen and Behrens, 1992).

Comparative biochemical studies between the malaria parasite, P.falciparum and its host have revealed differences in a number ofmetabolic pathways. One such distinction is that the parasite reliesexclusively on pyrimidine synthesis de novo because of its inability tosalvage preformed pyrimidines (Sherman, 1979). Moreover, the maturehuman red blood cell has no recognised requirement for pyrimidinenucleotides (Gero and O'Sullivan, 1990). Major efforts have beendirected towards the development of inhibitors of the pyrimidinebiosynthetic pathway (Hammond et al., 1985; Scott et al., 1986;Prapunwattana et al., 1988; Queen et al., 1990; Krungkrai et al., 1992),confirming its potential as a chemotherapeutic locus. Current researchinto the molecular biology of the key pyrimidine enzymes is envisionedas a powerful tool, not only to get a better understanding of theparasite's biochemistry, but also to explore specific differencesbetween the parasite and the mammalian enzymes.

Glutamine-dependent carbamoyl phosphate synthetase (CPSII, EC 6.3.5.5)catalyses the first committed and rate-limiting step in the de novopyrimidine biosynthetic pathway of eukaryotic organisms (Jones, 1980).Moreover, because it catalyzes a complex reaction involving threecatalytic units and several substrates and intermediates, it is a veryinteresting enzyme to study from a biochemical point of view. Thestructural relationship of CPSII to other pyrimidine enzymes varies indifferent organisms, making it a good subject for evolutionary studies.

The paucity of material that can be obtained from malarial cultures hashampered the isolation of adequate amounts of pure protein for analysis.The difficulty in purifying CPS is further augmented by its inherentinstability. Studies using crude extracts from P. berghei (a rodentmalaria) revealed a high molecular weight protein containing CPSactivity, which was assumed to be associated with ATCase (Hill et al.,1981), a situation also found in yeast (Makoff and Radford, 1978).However, recent analysis by Krungkrai and co-workers (1990) detectedseparate CPSII and ATCase activities in P. berghei. Although CPSactivity has been detected in P. falciparum (Reyes et al., 1982) untilthis current study there is no indication of its size nor its linkagewith other enzymes in the pathway.

The glutamine-dependent activity of CPSII can be divided into two steps:(1) a glutaminase (GLNase) reaction which hydrolyzes glutamine (Gln) andtransfers ammonia to the site of the carbamoyl phosphate synthetase; and(2) a synthetase reaction where carbamoyl phosphate is synthesised fromtwo molecules of adenosine triphosphate (ATP), bicarbonate and ammonia.The second activity involves three partial reactions: (a) the activationof bicarbonate by ATP; (b) the reaction of the activated speciescarboxyphosphate with ammonia to form carbamate; and (c) theATP-dependent phosphorylation of carbamate to form carbamoyl phosphate(powers and Meister, 1978). Hence, there are two major domains in CPSII,the glutamine amidotransferase domain (GAT) and the carbamoyl phosphatesynthetase domain (CPS) or simply synthetase domain. The glutaminasedomain (GLNase) is a subdomain of GAT, while there are two ATP-bindingsubdomains in the synthetase domain.

In view of the similarities between the glutamine amidotransferasedomain of CPS and other amidotransferases, it has been proposed thatthese subunits arose by divergent evolution from a common ancestral gene(=20 kDa) representing the GLNase domain and that particular evolutionof the CPS GAT domain (=42 kDa which includes the putative structuraldomain only present in CPS) must have involved fusions and/or insertionsof other sequences (Werner et al., 1985). The GAT of mammalian CPSI genehas been proposed to be formed by a simple gene fusion event at the 5'end of this ancestral gene with an unknown gene (Nyunoya et al., 1985).

The genes for the larger synthetase domains of various organisms werepostulated to have undergone a gene duplication of an ancestral kinasegene resulting in a polypeptide with two homologous halves (Simmer etal., 1990). Unlike the subunit structure of E. coli andarginine-specific CPS of yeast, a further fusion of the genes encodingGAT and the synthetase domains was suggested to have formed the singlegene specific for pyrimidine biosynthesis in higher eukaryotes.Conversely, Simmer and colleagues (1990) proposed that thearginine-specific CPS's (like cpa1 and cpa2 in yeast) as well as ratemitochondrial CPSI arose by defusion from the pyrimidine chimera.

DESCRIPTION OF THE INVENTION

The present inventors have isolated and characterised the complete geneencoding the CPSII enzyme from P. falciparum (pfCPSII). Reported here isthe sequence including 5' and 3' untranslated regions. In so doing, thepresent inventors have identified the respective glutaminase andsynthetase domains. Unlike CPSII genes in yeast, D. discoideum, andmammals, there is no evidence for linkage to the subsequent enzyme,aspartate transcarbamoylase (ATCase). This is in contrast to the reportby Hill et al., (1981) for the enzymes from P. berghei. The presentinventors have, however, found two large inserts in the P. falciparumgene of a nature that does not appear to have been previously described.

Accordingly, in a first aspect, the present invention consists in anucleic acid molecule encoding carbamoyl phosphate synthetase II ofPlasmodium falciparum, the nucleic acid molecule including a sequencesubstantially as shown in Table 1 from 1 to 7176, or from 1 to 750, orfrom 751 to 1446, or from 1447 to 2070, or from 2071 to 3762, or from3763 to 5571, or from 5572 to 7173, or from 1 to 3360, or from 2071 to6666, or from 2071 to 7173, or a functionally equivalent sequence.

In a preferred embodiment of the present invention, the nucleic acidmolecule includes a sequence shown in Table 1 from -1225 to 7695 or afunctionally equivalent sequence.

In a second aspect, the present invention consists in an isolatedpolypeptide, the polypeptide including an amino acid sequencesubstantially as shown in Table 1 from 1 to 2391, from 483 to 690, from691 to 1254, 1858 to 2391, from 1 to 1120, from 691 to 2222, or from 691to 2391.

As used herein the term "functionally equivalent sequence" is intendedto cover minor variations in the nucleic acid sequence which, due todegeneracy in the code, do not result in the sequence encoding adifferent polypeptide.

In a third aspect the present invention consists in a method ofproducing Plasmodium falciparum carbamoyl phosphate synthetase II, themethod comprising culturing a cell transformed with the nucleic acidmolecule of the first aspect of the present invention under conditionswhich allow expression of the nucleic acid sequence, and recovering theexpressed carbamoyl phosphate synthetase II.

The cells may be either bacteria or eukaryotic cells. Examples ofpreferred cells include E. coli, yeast, and Dictyostelium discoideum.

As will be readily understood by persons skilled in this field, theelucidation of the nucleotide sequence for CPSII enables the productionof a range of therapeutic agents. These include antisense nucleotides,ribozymes, and the targeting of RNA and DNA sequences using otherapproaches, e.g., triplex formation.

As can be seen from a consideration of the sequence set out in Table 1the Plasmodium falciparum CPSII gene includes two inserted sequences notfound in other carbamoyl phosphate synthetase genes. The first insertedsequence separates the putative structural domain and the glutiminasedomain whilst the second inserted sequence separates the two ATP bindingsubdomains of the synthetase subunit CPSa and CPSb.

                                      TABLE 1                                     __________________________________________________________________________    Nucleotide and Deduced Amino Acid Sequence of the                             Carbamoyl Phosphate Synthetase II Gene from Plasmodium                        falciparum (SEQ ID NOS: 1 and 2)                                              __________________________________________________________________________     ##STR1##                                                                      ##STR2##                                                                      ##STR3##                                                                      ##STR4##                                                                      ##STR5##                                                                      ##STR6##                                                                      ##STR7##                                                                      ##STR8##                                                                      ##STR9##                                                                      ##STR10##                                                                     ##STR11##                                                                     ##STR12##                                                                     ##STR13##                                                                     ##STR14##                                                                     ##STR15##                                                                     ##STR16##                                                                     ##STR17##                                                                     ##STR18##                                                                     ##STR19##                                                                     ##STR20##                                                                     ##STR21##                                                                     ##STR22##                                                                     ##STR23##                                                                     ##STR24##                                                                     ##STR25##                                                                     ##STR26##                                                                     ##STR27##                                                                     ##STR28##                                                                     ##STR29##                                                                     ##STR30##                                                                     ##STR31##                                                                     ##STR32##                                                                     ##STR33##                                                                     ##STR34##                                                                     ##STR35##                                                                     ##STR36##                                                                     ##STR37##                                                                     ##STR38##                                                                     ##STR39##                                                                     ##STR40##                                                                     ##STR41##                                                                     ##STR42##                                                                     ##STR43##                                                                     ##STR44##                                                                     ##STR45##                                                                     ##STR46##                                                                     ##STR47##                                                                     ##STR48##                                                                     ##STR49##                                                                     ##STR50##                                                                     ##STR51##                                                                     ##STR52##                                                                     ##STR53##                                                                     ##STR54##                                                                     ##STR55##                                                                     ##STR56##                                                                     ##STR57##                                                                     ##STR58##                                                                     ##STR59##                                                                     ##STR60##                                                                     ##STR61##                                                                     ##STR62##                                                                     ##STR63##                                                                     ##STR64##                                                                     ##STR65##                                                                     ##STR66##                                                                     ##STR67##                                                                     ##STR68##                                                                     ##STR69##                                                                     ##STR70##                                                                     ##STR71##                                                                     ##STR72##                                                                     ##STR73##                                                                     ##STR74##                                                                     ##STR75##                                                                     ##STR76##                                                                     ##STR77##                                                                     ##STR78##                                                                     ##STR79##                                                                     ##STR80##                                                                     ##STR81##                                                                     ##STR82##                                                                     ##STR83##                                                                     ##STR84##                                                                     ##STR85##                                                                     ##STR86##                                                                     ##STR87##                                                                     ##STR88##                                                                     ##STR89##                                                                     ##STR90##                                                                     ##STR91##                                                                     ##STR92##                                                                     ##STR93##                                                                     ##STR94##                                                                     ##STR95##                                                                     ##STR96##                                                                     ##STR97##                                                                     ##STR98##                                                                     ##STR99##                                                                     ##STR100##                                                                    ##STR101##                                                                    ##STR102##                                                                    ##STR103##                                                                    ##STR104##                                                                    ##STR105##                                                                    ##STR106##                                                                    ##STR107##                                                                    ##STR108##                                                                    ##STR109##                                                                    ##STR110##                                                                    ##STR111##                                                                    ##STR112##                                                                    ##STR113##                                                                    ##STR114##                                                                    ##STR115##                                                                    ##STR116##                                                                    ##STR117##                                                                    ##STR118##                                                                    ##STR119##                                                                    ##STR120##                                                                    ##STR121##                                                                    ##STR122##                                                                    ##STR123##                                                                    ##STR124##                                                                    ##STR125##                                                                    ##STR126##                                                                    ##STR127##                                                                    ##STR128##                                                                    ##STR129##                                                                    ##STR130##                                                                    ##STR131##                                                                    ##STR132##                                                                    ##STR133##                                                                    ##STR134##                                                                    ##STR135##                                                                    ##STR136##                                                                    ##STR137##                                                                    ##STR138##                                                                    ##STR139##                                                                    ##STR140##                                                                    ##STR141##                                                                    ##STR142##                                                                    ##STR143##                                                                    ##STR144##                                                                    ##STR145##                                                                    ##STR146##                                                                    ##STR147##                                                                    ##STR148##                                                                    ##STR149##                                                                    ##STR150##                                                                   __________________________________________________________________________     The GAT domain is make up of two subdomains: a putative structural domain     (1750) and a glutaminase domain (1447-2070). These two subdomains are         separated by a first inserted sequence (751-1446, underlined). The two AT     binding subdomains of the synthetase subunit, CPSa (2071-3762) and CPSb       (5572-5173) are separated by a second inserted sequence (3763-5571,           underlined).                                                             

As these inserted sequences are not found in other carbamoyl phosphatesynthetase genes they represent prime targets for therapies including,but not limited to, antisense nucleotides, ribozymes and triplex formingnucleotides as there is a decreased likelihood of deleterious reactionwith host homologues of the gene.

Antisense RNA molecules are known to be useful for regulating geneexpression within the cell. Antisense RNA molecules which arecomplementary to portion(s) of CPSII can be produced from the CPSIIsequence. These antisense molecules can be used as either diagnosticprobes to determine whether or not the CPSII gene is present in a cellor can be used as a therapeutic to regulate expression of the CPSIIgene. Antisense nucleotides prepared using the CPSII sequence includenucleotides having complementarity to the CPSII mRNA and capable ofinterfering with its function in vivo and genes containing CPSIIsequence elements that can be just transcribed in living cells toproduce antisense nucleotides. The genes may include promoter elementsfrom messenger RNA (polymerase II) from cells, viruses, pathogens orstructural RNA genes (polymerase I & III) or synthetic promoterelements. A review of antisense design is provided in "Gene Regulation:Biology of Antisense RNA and DNA" R. P. Eirckson and J. G. Izant, RavenPress 1992. Reference may also be had to U.S. Pat. No. 5,208,149 whichincludes further examples on the design of antisense nucleotides. Thedisclosure of each of these references is incorporated herein byreference.

As used herein the term "nucleotides" include but are not limited tooligomers of all naturally-occurring deozyribonucleotides andribonucleotides as well as any nucleotide analogues. Nucleotideanalogues encompass all compounds capable of forming sequence-specificcomplexes (eg duplexes or hetroduplexes) with another nucleotideincluding methylphosphonates or phosphorothioates but may haveadvantageous diffusion or stability properties. The definition ofnucleotides includes natural or analogue bases linked by phosphodiesterbonds, peptide bonds or any other covalent linkage. These nucleotidesmay be synthesised by any combination of in vivo in living cells,enzymatically in vitro or chemically.

Ribozymes useful in regulating expression of the CPSII gene includenucleotides having CPSII sequence for specificity and catalytic domainsto promote the cleavage of CPSII mRNA in vitro or in vivo. The catalyticdomains include hammerheads, hairpins, delta-virus elements, ribosomeRNA introns and their derivatives. Further information regarding thedesign of ribozymes can be found in Haseloff, J. & Gerlach, W. L. (1988)Nature 334, 585; Kruger, K., Grabowski, P. J., Zaug, A. J., Sands, J.,Gottschling, D. E. & Cech, T. R. (1982) Cell 31, 147; InternationalPatent Application No. WO 88/04300, U.S. Pat. Nos. 4,987,071 and5,254,678. The disclosure of each of these references is incorporatedherein by reference. The catalytic elements may enhance the artificialregulation of a CPSII target mRNA by accelerating degradation or someother mechanism.

Triple helix oligonucleotides can be used to inhibit transcription fromthe genome. Given the sequence provided herein for the CPSII gene itwill now be possible to design oligonucleotides which will formtriplexes thereby inhibiting transcription of the CPSII gene.Information regarding the generation of oligonucleotides suitable fortriplex formation can be found in a Griffin et al (Science 245:967-971(1989)) this disclosure of this reference is incorporated hereinby reference.

Triplex agents include all nucleotides capable of binding to the CPSIIgene through formation of the complex with DNA or chromatin. Theinteraction can be through formation of a triple-stranded Hoogsteenstructure or other mechanisms such as strand invasion that relies on theCPSII sequence information.

Accordingly, in a fourth aspect the present invention consists in aribozyme capable of cleaving carbamoyl phosphate synthetase II mRNA, theribozyme including sequences complementary to portions of mRNA obtainedfrom the nucleic acid molecule of the first aspect of the presentinvention.

In a preferred embodiment of this aspect of the present invention theribozyme includes sequences complementary to mRNA obtained from thefirst or second inserted sequences of the nucleic acid molecule of thefirst aspect of the present invention.

In a fifth aspect the present invention consists in an antisenseoligonucleotide capable of blocking expression of the nucleic acidmolecule of the first aspect of the present invention.

As stated above, in one aspect the present invention relates to a methodof producing CPSII by rcombinant technology. The protein produced bythis method and the polypeptides of the present invention will be usefulin in vitro drug binding studies in efforts to develop otheranti-malarial therapeutics.

In order that the nature of the present invention may be more clearlyunderstood the method by which the P. falciparum CPSII gene was clonedwill now be described with reference to the following example andFigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a summary of a "gene walking" strategy used to clone andsequence the full length P. falciparum carbamoyl phosphate synthetase IIgene.

EXAMPLE

The conventional way to screen for genes of which the amino acidsequence had not been previously determined is via heterologous probing,i.e. with gene fragments of the target enzyme from closely relatedorganisms. This has proved to be unsuccessful for several workers withPlasmodium falciparum largely due to the unusually high A-T content ofits genome. After initial unfruitful attempts to isolate the CPSII genein Plasmodium falciparum using a yeast ura2 gene fragment (Souciet etal., 1989), the present invention opted to amplify part of the CPSIIgene using the polymerase chain reaction (PCR) (Saiki et al.,1988) witha view to use the amplified product as probe for screening.

The present invention isolated and cloned a PCR product usingoligonucleotides designed from conserved sequences from the aminoterminal GAT domain and the first half of the synthetase domain of theCPS gene. Nucleotide sequencing confirmed that a portion of the CPSIIgene had been obtained. Total parasite DNA was fragmented with arestriction enzyme and subjected to Southern analysis using theCPSII-specific gene probe. The sizes of DNA fragments hybridizing to thegene probe were determined then the DNA in the corresponding bands wereused for the construction of a "mini-library". In this way a smallerpopulation of clones were screened for the pf CPSII gene.

To isolate the full length of pf CPSII gene, a series of mini-librarieswere constructed utilising different segments of known sequence to gaininformation of the unknown flanking regions both towards the 5' and 3'termini of the gene using "gene-walking". The strategy employed issummarized in FIG. 1.

In the first Southern analysis, total P. falciparum DNA was digestedwith HindIII and EcoRI and hybridisation was carried out using thepfCPSII 453 PCR product. A 3.0 kb HindIII and a smaller EcoRI fragmenthybridised to the probe. Subsequent screening of a HindIII pTZ18Umini-library resulted in the isolation of a recombinant that contained a3.0 kb pfCPSII gene fragment, CPS2. The 453 bp PCR product was localisedin the middle of this segment.

Two regions from both the 5' and 3' ends of CPS2 were used to isolateneighbouring sequences at either end in order to obtain the further genesequences. A HindIII/EcoRI fragment from the 5' end of CPS2 wasinstrumental in isolating a further 1.5 kb fragment, CPS1 consisting ofthe complete 5' region of the gene and some non-encoding sequences.

A 550 bp inverse PCR (IPCR; Triglia et al., 1988) product was obtainedwith the aid of known sequences from the 3' end of CPS2.

This IPCR product was used to screen for the 3' region flanking CPS2. A3.3 kb HindIII recombinant containing CPS3 as well as a related 3.3 kbXBaI clone (not presented in FIG. 1) were isolated by the mini-librarytechnique. Using a 200 bp XbaI/HindIII fragment from the 3' end of CPS3,a 1.3 kb XbaI segment, CPS4 was cloned which contained the putative stopcodon and some 3' non-coding region.

Combining these four gene gragments (CPS1, CPS2, CPS3 and CPS4)excluding their overlaps, gives a total of 8.8 kb consisting ofapproximately 7.0 kb coding and 1.8 flanking sequences.

The complete nucleotide sequence of the CPSII gene in P. falciparum,together with its 5' and 3' flanking sequences, is presented in Table 1.

As will be readily appreciated by those skilled in the art the isolationof this gene and its sequencing by the present inventors opens up arange of new avenues for treatment of Plasmodium falciparum infection.The present invention enables the product of quantities of thePlasmodium falciparum carbamoyl phosphate synthetase II enzyme usingrecombinant DNA technology. Characterisation of this enzyme may enableits use as a chemotherapeutic loci.

The isolation of this gene also will enable the production of antisensemolecules, ribozymes or other gene inactivation agents which can be usedto prevent the multiplication of the parasite in infected individuals.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

REFERENCES

Cox, F. E. G. (1991) Malaria vaccines: while we are waiting.Parasitology Today 7: 189-190

Gero, A. M. and O'Sullivan, W. J. (1991) Purines and pyrimidines inmalarial parasites. Blood Cells 16: 467-498

Hammond, D. J. Burchell, J. R. and Pudrey, M. (1985) Inhibition ofpyrimidine biosynthesis de novo in Plasmodium falciparum by2.(4.t-butylcyclohexyl)-3-hydroxy-1, 4-naphthoquinine in vitro. Mol.Biochem. Parasitol 14: 97-109

Hill, B., Kilsby, J. Rogerson, G. W., McIntosh, R. T. and Ginger, C. D.(1981). The Enzymes of pyrimidine biosynthesis in a range of parasiticprotozoa and helminths. Mol. Biochem. Parasitol. 2: 123-134.

Johnson, C. Malaria back to plague us. Sydney Morning Herald, Nov. 13,1991.

Jones, M. E. (1980) Pyrimidine nucleotide biosynthesis in animals:genes, enzymes and regulation of UMP biosynthesis. Annu. Rev. Biochem.49: 253-279.

Krungkrai, J. Cerami, A. and Henderson, G. B. (1990) Pyrimidinebiosynthesis in parasitic protozoa: purification of a monofunctionaldihydroorotase from Plasmodium berghei and Crithidia fasciculata.Biochemistry 29: 6270-6275.

Krungkrai, J. Krungkrai, S. R. and Phakanont, K. (1992) Antimalarialactivity of orotate analogs that inhibit dihydrootase and dihydroorotatedehydrogenase. Biochem. Pharmacol. 43: 1295-1301.

Marshal, E. (1991) Malaria parasite gaining ground against science.Science 2: 190.

Nyunoya, H., Broglie, K. E., Widgren, W. E. and Lusty C. J. (1985)Characterization and derivation of the gene coding for mitochondrialcarbamyl phosphate synthetase I of rat. J. Biol. Chem. 260: 9346-9356.

Prapunwattana, P., O'Sullivan, W. J. and Yuthavong, Y. (1988) Depressionof Plasmodium falciparum dihydroorotate dehydrogenase activity in invitro culture by tetracycline. Mol. Biochem. 27: 119-124.

Queen, S. A., Vander Jagt, D. L. and Reyes, P. (1990) In vitrosusceptibilities of Plasmodium falciparum to compounds which inhibitnucleotide metabolism. Antimicrob. Agents Chemother. 34: 1393-1398.

Reyes, P., Rathod, P. K., Sanchez, D. J. Mrema, J. E. K., Rieckmann, K.H. and Heidrich, H. G. (1982) Enzymes of purine and pyrimidinemetabolism from the human malaria parasite, Plasmodium falciparum. Mol.Biochem. Parasitol. 5: 275-290.

Rubino S. D., Nyunoya, H. and Lusty, C. J. (1986) JBC261(24):11320-11327.

Saiki, R. K., Gelfand, D. H., Stoffel, S., Scharf, S. J., Higuchi, R.,Horn, G. T., Mullis K. B. and Erlich H. A. (1988) Science 239:487-491.

Scott, H. V., Gero, A. M. and O'Sullivan, W. J. (1986) In vitroinhibition of Plasmodium falciparum by pyrazofurin, an inhibitor ofpyrimidine biosynthesis de novo. Mol. Biochem. Parasitol. 18: 3-15.

Sherman, I. W. (1979) Biochemistry of Plasmodium (malarial parasites)Microbiol. Rev. 43: 453-495.

Simmer, J. P., Kelly, R. E., Rinker, Jr., A. G., Scully, J. L. and EvansD. R. (1990) Mammalian carbamyl phosphate synthetase (CPS). J. Biol.Chem 265: 10395-10402.

Simmer, J. P., Kelly, R. E., Austin, G. R., Jr., Scully, J. L. andEvans, D. R. (1990) JBC 285(18):10395-10402.

Souciet, J. L., Nagy, M., Le Gouar, M., Lacroute, F. and Potier, S.(1989) Gene (Amst.) 79: 59-70.

Triglia, T., Peterson, M. G. and Kemp, D. J. (1988) PNAS 16:8186.

Werner, M., Feller, A. and Pierard, A. (1985) Nucleotide sequence ofyeast gene CPA1 encoding the small subunit of argine-pathwaycarbamoyl-phosphate synthetase. Eur. J. Biochem. 146: 371-381.

    __________________________________________________________________________    SEQUENCE LISTING                                                              (1) GENERAL INFORMATION:                                                      (iii) NUMBER OF SEQUENCES: 2                                                  (2) INFORMATION FOR SEQ ID NO:1:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 8920 base pairs                                                   (B) TYPE: nucleic acid                                                        (C) STRANDEDNESS: single                                                      (D) TOPOLOGY: linear                                                          (ii) MOLECULE TYPE: genomic                                                   (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                                       GAATTCCTTCAGCCAAAAAAAATGACAACGCAAATTTTAAGAAAAGAAAAACAATCGACT60                CGTCTTTGAATGAGGTTAGAAATTCGATACGTGAAAGGGACTTAAGAAGGCTTAACAGAG120               AAAAGAGTAAAATCTTATAAGCATTTGAAGGAAAAAATAATAAAATAAAAAAATAAAAAG180               ATAAAAAATATTTATATTTGATATGTAGTATATATAATGATTATTCATATTAATAACATA240               GATAAAAAACTTTTTTTTTTTTTTTTTTTCTTTATATTTATTAACAATACATTTAAGTTA300               TTTTATATATATATATATATATATATATATATATATATATATATATGTTTGTGTGTTCAT360               TTGTTTATAAAATTACTTGAAATATAAAACTTATTAATATATTTCCAATTAATATGAATA420               CAATTATTAATATTTTGATGTGTACACATTAATATAGTTTTACACTTCTTATAATAAAAC480               CATCCTATATATTATACACAATATATAATACTCCCCAATATTGTGGTTCCTATAATTTTA540               TTTATATATTTATTTATTAATTTATTCATTTATTTATTTTTTTTCTTAGTTTATAAAATA600               GTAATTCTACTAATTTAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGAAAAAAAAAAAATT660               TACATATGAAAAATGAACTTGTATATGTAAATTTATAAATATTTTAAACATAAATATAAA720               TGTATAAAAAAAAAAAAGAAAAATGGGAAAAAATAATATAGATATATATATAAATATATA780               TATATATATAATTATTGGGGATATTCTCTGAATCATAGGTCTTAAACAGTTTTATTCTTT840               TAACATCACAAAGTTGTTATTAAAAGTATATATATCTTATTGGTTCCTATATAAAACTAT900               AGTATTCTATAATATATTCTGTATATTTCATTTTATCATTTGTAAGCAATCCCTATTTAT960               TATAATTATTATTTTTTTTTTTATAAAAGAGGTATAAAACAGTTTATTCAATTTTTTTCC1020              TAAAGGAGCAACCTTCAGTCAATTTACATTTTCCACCGGTTGGTTGGCACAACATAATGT1080              TACAGCTAAAAAAAGAAAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAATATATATAT1140              ATATATATATATATACATAATATGTACAATGCTACCATACAAGTATATAAATTTTTCAAC1200              ATTGTTGTGATGTTGCATTTTTCTTATGTATATTTCTTTTAAATATAATTTATATATATA1260              TATATATATATATATATATATATTTGTTCTTATAGATTTTAAAACAGTTGGGAGGTTAAT1320              TCTTGAAGATGGTAACGAATTTGTAGGGTACAGTGTAGGTTACGAAGGGTGTAAAGGAAA1380              TAATAGTATATCATGTCATAAGGAGTATAGAAATATTATTAATAATGATAATAGCAAGAA1440              TAGTAATAATTCATTTTGTAATAATGAAGAAAACAATTTGAAAGATGATTTATTATATAA1500              AAATAGTCGATTAGAAAATGAAGATTTTATTGTTACAGGTGAAGTTATATTTAATACAGC1560              TATGGTTGGATATCCTGAAGCTTTAACGGACCCAAGTTATTTTGGTCAAATATTAGTTTT1620              AACATTTCCTTCTATTGGTAATTATGGTATTGAAAAAGTAAAACATGATGAAACGTTTGG1680              ATTAGTACAAAATTTTGAAAGTAATAAAATTCAAGTACAAGGTTTAGTTATTTGTGAATA1740              TTCGAAGCAATCATATCATTACAATTCTTATATTACCTTAAGTGAATGGTTAAAGATTTA1800              TAAAATTCCATGTATAGGTGGTATAGATACAAGAGCCTTAACAAAACTTTTAAGAGAAAA1860              AGGTAGTATGTTAGGTAAAATAGTTATATATAAAAACAGACAACATATTAATAAATTATA1920              TAAAGAAATTAATCTTTTTGATCCTGGTAATATAGATACTCTAAAATATGTATGTAATCA1980              TTTTATACGTGTTATTAAGTTGAATAATATTACATATAATTATAAAAATAAGGAAGAATT2040              TAATTATACCAATGAAATGATTACTAATGATTCTTCAATGGAAGATCATGATAATGAAAT2100              TAATGGTAGTATTTCTAATTTTAATAATTGTCCAAGTATCTCTAGTTTTGATAAAAGTGA2160              ATCGAAAAATGTTATTAATCATACATTGTTAAGAGATAAAATGAACCTAATAACTTCATC2220              TGAAGAATATCTGAAAGATCTTCATAATTGTAATTTTAGTAATAGTAGTGATAAAAATGA2280              TTCTTTTTTTAAGTTATATGGTATATGTGAATATGATAAATATTTAATTGACCTTGAAGA2340              AAATGCTAGCTTTCATTATAATAATGTAGATGAATATGGATATTATGATGTTAATAAAAA2400              TACAAATATTCTATCTAATAATAAAATAGAACAAAACAACAATAACGAAAATAACAAAAA2460              TAACAAAAATAACAACAATAACGAGGTTGATTATATAAAGAAAGATGAGGATAATAATGT2520              CAATAGTAAGGTCTTTTATAGCCAATATAATAATAATGCACAAAATAATGAACATACCGA2580              ATTTAATTTAAATAATGATTATTCTACTTATATTAGAAAGAAAATGAAAAATGAAGAATT2640              CCTTAATTTGGTAAACAAAAGAAAAGTAGACCATAAAGAAAAAATTATTGTTATTGTTGA2700              TTGTGGTATTAAAAATAGTATAATCAAAAATTTAATAAGACACGGTATGGATCTTCCATT2760              AACATATATTATTGTACCTTATTATTACAATTTTAATCATATAGATTATGATGCAGTTCT2820              TTTATCTAATGGTCCTGGAGATCCTAAAAAGTGTGATTTCCTTATAAAAAATTTGAAAGA2880              TAGTTTAACAAAAAATAAAATTATATTTGGTATTTGTTTAGGTAATCAACTATTAGGTAT2940              ATCATTAGGTTGTGACACATATAAAATGAAATATGGTAATAGAGGTGTTAATCAACCCGT3000              AATACAATTAGTAGATAATATATGTTACATTACCTCACAAAATCATGGATACTGTTTAAA3060              GAAAAAATCAATTTTAAAAAGAAAAGAGCTTGCGATTAGTTATATAAATGCTAATGATAA3120              ATCTATAGAAGGTATTTCACATAAAAATGGAAGATTTTATAGTGTCCAGTTTCATCCTGA3180              GGGTAATAATGGTCCTGAAGATACATCATTTTTATTTAAGAATTTTCTTTTAGATATCTT3240              TAATAAGAAAAAACAATATAGAGAATATTTAGGATATAATATTATTTATATAAAAAAGAA3300              AGTGCTTCTTTTAGGTAGTGGTGGTTTATGTATAGGACAAGCAGGAGAATTCGATTATTC3360              AGGAACACAAGCAATTAAAAGTTTAAAAGAATGTGGTATATATGTTATATTAGTTAATCC3420              TAACATAGCAACTGTTCAAACATCAAAAGGTTTGGCAGATAAGGTATACTTTTTACCAGT3480              TAATTGTGAATTTGTAGAAAAAATTATTAAAAAGGAAAAACCTGATTTTATTTTATGTAC3540              ATTTGGTGGTCAGACAGCTTTAAATTGTGCTTTAATGTTAGATCAAAAAAAAGTATTGAA3600              AAAGAATAATTGTCAATGTTTAGGTACATCTTTAGAATCTATAAGAATAACAGAAAATAG3660              AACATTATTTGCTGAAAAATTAAAAGAAATTAATGAAAGAATAGCTCCATATGGTAGTGC3720              AAAAAATGTTAATCAAGCTATTGATATAGCTAATAAAATAGGATATCCAATATTAGTACG3780              TACAACATTTTCGTTAGGAGGATTAAATAGTAGTTTCATAAATAATGAAGAAGAACTTAT3840              CGAAAAATGTAATAAAATATTTTTACAAACTGATAATGAAATATTTATAGATAAATCATT3900              ACAAGGATGGAAAGAAATAGAATATGAATTATTAAGAGATAATAAAAATAATTGTATAGC3960              TATATGTAATATGGAAAATATAGATCCATTAGGTATACATACAGGAGATAGTATAGTTGT4020              TGCACCTTCACAAACATTAAGTAATTATGAATATTATAAATTTAGAGAAATAGCATTAAA4080              GGTAATTACACATTTAAATATTATAGGAGAATGTAATATACAATTTGGTATAAATCCACA4140              AACAGGAGAATATTGTATTATTGAAGTTAATGCTAGGCTTAGTAGAAGTTCAGCATTAGC4200              TTCTAAAGCTACTGGTTATCCACTTGCTTATATATCAGCAAAAATAGCCTTGGGATATGA4260              TTTGATAAGTTTAAAAAATAGCATAACTAAAAAAACAACTGCCTGTTTTGAACCCTCTCT4320              AGATTACATTACAACAAAAATACCACGATGGGATTTAAATAAATTTGAGTTTGCTTCTAA4380              TACAATGAATAGTAGTATGAAAAGTGTAGGAGAAGTTATGTCTATAGGTAGAACCTTTGA4440              AGAATCTATACAAAAATCTTTAAGATGTATTGATGATAATTATTTAGGATTTAGTAATAC4500              GTATTGTATAGATTGGGATGAAAAGAAAATTATTGAAGAATTAAAAAATCCATCACCAAA4560              AAGAATTGATGCTATACATCAAGCTTTCCATTTAAATATGCCTATGGATAAAATACATGA4620              GCTGACACATATTGATTATTGGTTCTTACATAAATTTTATAATATATATAATTTACAAAA4680              TAAGTTGAAAACGTTAAAATTAGAGCAATTATCTTTTAATGATTTGAAGTATTTTAAGAA4740              GCATGGTTTTAGTGATAAGCAAATAGCTCACTACTTATCCTTCAACACAAGCGATAATAA4800              TAATAATAATAATAATATTAGCTCATGTAGGGTTACAGAAAATGATGTTATGAAATATAG4860              AGAAAAGCTAGGATTATTTCCACATATTAAAGTTATTGATACCTTATCAGCCGAATTTCC4920              GGCTTTAACTAATTATTTATATTTAACTTATCAAGGTCAAGAACATGATGTTCTCCCATT4980              AAATATGAAAAGGAAAAAGATATGCACGCTTAATAATAAACGAAATGCAAATAAGAAAAA5040              AGTCCATGTCAAGAACCACTTATATAATGAAGTAGTTGATGATAAGGATACACAATTACA5100              CAAAGAAAATAATAATAATAATAATATGAATTCTGGAAATGTAGAAAATAAATGTAAATT5160              GAATAAAGAATCCTATGGCTATAATAATTCTTCTAATTGTATCAATACAAATAATATTAA5220              TATAGAAAATAATATTTGTCATGATATATCTATAAACAAAAATATAAAAGTTACAATAAA5280              CAATTCCAATAATTCTATATCGAATAATGAAAATGTTGAAACAAACTTAAATTGTGTATC5340              TGAAAGGGCCGGTAGCCATCATATATATGGTAAAGAAGAAAAGAGTATAGGATCTGATGA5400              TACAAATATTTTAAGTGCACAAAATTCAAATAATAACTTTTCATGTAATAATGAGAATAT5460              GAATAAAGCAAACGTTGATGTTAATGTACTAGAAAATGATACGAAAAAACGAGAAGATAT5520              AAATACTACAACAGTATTTATGGAAGGTCAAAATAGTGTTATTAATAATAAGAATAAAGA5580              GAATAGTTCTTTATTGAAAGGTGATGAAGAAGATATTGTGATGGTAAATTTAAAAAAGGA5640              AAATAATTATAATAGTGTAATTAATAATGTAGATTGTAGGAAAAAGGATATGGATGGAAA5700              AAATATAAATGATGAATGTAAAACATATAAGAAAAATAAATATAAAGATATGGGATTAAA5760              TAATAATATAGTAGATGAGTTATCCAATGGAACATCACATTCAACTAATGATCATTTATA5820              TTTAGATAATTTTAATACATCAGATGAAGAAATAGGGAATAATAAAAATATGGATATGTA5880              TTTATCTAAGGAAAAAAGTATATCTAATAAAAACCCTGGTAATTCTTATTATGTTGTAGA5940              TTCCGTATATAATAATGAATACAAAATTAATAAGATGAAAGAGTTAATAGATAACGAAAA6000              TTTAAATGATGAATATAATAATAATGTTAATATGAATTGTTCTAATTATAATAATGCTAG6060              TGCATTTGTAAATGGAAAGGATAGAAATGATAATTTAGAAAATGATTGTATTGAAAAAAA6120              TATGGATCATACATACAAACATTATAATCGTTTAAACAATCGTAGAAGTACAAATGAGAG6180              GATGATGCTTATGGTAAACAATGAAAAAGAGAGCAATCATGAGAAGGGCCATAGAAGAAA6240              TGGTTTAAATAAAAAAAATAAAGAAAAAAATATGGAAAAAAATAAGGGAAAAAATAAAGA6300              CAAAAAGAATTATCATTATGTTAATCATAAAAGGAATAATGAATATAATAGTAACAATAT6360              TGAATCGAAGTTTAATAATTATGTTGATGATATAAATAAAAAAGAATATTATGAAGATGA6420              AAATGATATATATTATTTTACACATTCGTCACAAGGTAACAATGACGATTTAAGTAATGA6480              TAATTATTTAAGTAGTGAAGAATTGAATACTGATGAGTATGATGATGATTATTATTATGA6540              TGAAGATGAAGAAGATGACTATGACGATGATAATGATGATGATGATGATGATGATGATGA6600              TGGGGAGGATGAGGAGGATAATGATTATTATAATGATGATGGTTATGATAGCTATAATTC6660              TTTATCATCTTCAAGAATATCAGATGTATCATCTGTTATATATTCAGGGAACGAAAATAT6720              ATTTAATGAAAAATATAATGATATAGGTTTTAAAATAATCGATAATAGGAATGAAAAAGA6780              GAAAGAGAAAAAGAAATGTTTTATTGTATTAGGTTGTGGTTGTTATCGTATTGGTAGTTC6840              TGTAGAATTTGATTGGAGTGCTATACATTGTGTAAAGACCATAAGAAAATTAAACCATAA6900              AGCTATATTAATAAATTGTAACCCAGAAACTGTAAGTACAGATTATGATGAAAGTGATCG6960              TCTATATTTTGATGAAATAACAACAGAAGTTATAAAATTTATATATAACTTTGAAAATAG7020              TAATGGTGTGATTATAGCTTTTGGTGGACAAACATCAAATAATTTAGTATTTAGTTTATA7080              TAAAAATAATGTAAATATATTAGGATCAGTGCACAAAGTGTTGATTGTTGTGAAAATAGG7140              AATAAATTTTCGCACTTATGTGATTCTTAAAATTGATCAACCGAAATGGAATAAATTTAC7200              AAAATTATCCAAGGCTATACAATTTGCTAATGAGGTAAAATTTCCTGTATTAGTAAGACC7260              ATCGTATGTATTATCTGGTGCAGCTATGAGAGTTGTAAATTGTTTTGAAGAATTAAAAAA7320              CTTTTTAATGAAGGCAGCTATTGTTAGTAAAGATAATCCTGTTGTAATATCAAAATTTAT7380              TGAGAATGCTAAAGAAATAGAAATAGATTGTGTTAGTAAAAATGGTAAAATAATTAATTA7440              TGCTATATCTGAACATGTTGAAAATGCTGGTGTACATTCAGGTGATGCAACATTAATATT7500              ACCTGCACAAAATATATATGTTGAAACACATAGGAAAATAAAGAAAATATCCGAAAAGAT7560              TTCAAAATCATTAAATATATCTGGTCCATTTAATATACAATTTATATGTCATCAAAATGA7620              AATAAAAATTATTGAATGTAATTTAAGAGCATCTAGAACTTTTCCATTTATATCAAAAGC7680              TCTAAATCTAAACTTTATAGATTTAGCTACAAGGATATTAATGGGTTATGACGTCAAACC7740              AATTAATATATCATTAATTGATTTAGAATATACAGCTGTAAAAGCACCGATTTTCTCATT7800              TAATAGATTACATGGATCAGATTGTATACTAGGTGTAGAAATGAAATCTACAGGTGAAGT7860              AGCATGTTTTGGTTTAAATAAATATGAAGCTTTATTAAAATCATTAATAGCTACAGGTAT7920              GAAGTTACCCAAAAAATCAATACTTATAAGTATTAAAAATTTAAATAATAAATTAGCTTT7980              TGAAGAACCGTTCCAATTATTATTTTTAATGGGATTTACAATATATGCGACTGAAGGTAC8040              GTATGATTTCTACTCTAAATTTTTAGAATCTTTTAATGTTAATAAAGGTTCTAAATTTCA8100              TCAAAGACTTATTAAAGTTCATAATAAAAATGCAGAAAATATATCACCAAATACAACAGA8160              TTTAATTATGAATCATAAAGTTGAAATGGTTATTAATATAACTGATACATTAAAAACAAA8220              GGTTAGTTCAAATGGTTATAAAATTAGAAGATTAGCATCAGATTTCCAGGTTCCTTTAAT8280              AACTAATATGAAACTTTGTTCTCTTTTTATTGACTCATTATATAGAAAATTCTCAAGACA8340              AAAGGAAAGAAAATCATTCTATACCATAAAGAGTTATGACGAATATATAAGTTTGGTATA8400              AGCAAGAAATTATTCAATAAATTCGATTTAACATTACTTATTTATGTATTTATTAACTTT8460              CATTCCATAACAACATGAAAAGTATAAATATATAAATAGTAATATATAATATATAATATA8520              TATATATATATATATATATATATTTATTTATTTAATTATATTTACGTTTAAATATTAATA8580              AATGTTTTTATTAAATATGATCATTAATTTATATTGATTTATTTTTTTATAAATTTTTGT8640              TATATATACAAATTTTATTTATTCACTCATATGTATAAACCAAAATGGTTTTTTCAATTT8700              ACAAATAATTTTATAATTTTAATAAATTTATTAATTATAAAAAAAATAAAAATATATAAA8760              CATTAAAATGTATAAATTCTTTTAATTATATAATAATTTATAAATGTTATGATTTTTTTA8820              AAAAATTCAACGAAAAAAAAGAGGAACTGTATATACAAAAGGGACTATATATATGTATAT8880              ATATATATATATATATATGTTTTTTTTTCCTTATTCTAGA8920                                  (2) INFORMATION FOR SEQ ID NO:2:                                              (i) SEQUENCE CHARACTERISTICS:                                                 (A) LENGTH: 2391 amino acids                                                  (B) TYPE: amino acid                                                          (C) STRANDEDNESS: single                                                      (D) TOPOLOGY: linear                                                          (ii) MOLECULE TYPE: protein                                                   (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:                                       MetTyrIleSerPheLysTyrAsnLeuTyrIleTyrIleTyrIleTyr                              151015                                                                        IleTyrIlePheValLeuIleAspPheLysThrValGlyArgLeuIle                              202530                                                                        LeuGluAspGlyAsnGluPheValGlyTyrSerValGlyTyrGluGly                              354045                                                                        CysLysGlyAsnAsnSerIleSerCysHisLysGluTyrArgAsnIle                              505560                                                                        IleAsnAsnAspAsnSerLysAsnSerAsnAsnSerPheCysAsnAsn                              65707580                                                                      GluGluAsnAsnLeuLysAspAspLeuLeuTyrLysAsnSerArgLeu                              859095                                                                        GluAsnGluAspPheIleValThrGlyGluValIlePheAsnThrAla                              100105110                                                                     MetValGlyTyrProGluAlaLeuThrAspProSerTyrPheGlyGln                              115120125                                                                     IleLeuValLeuThrPheProSerIleGlyAsnTyrGlyIleGluLys                              130135140                                                                     ValLysHisAspGluThrPheGlyLeuValGlnAsnPheGluSerAsn                              145150155160                                                                  LysIleGlnValGlnGlyLeuValIleCysGluTyrSerLysGlnSer                              165170175                                                                     TyrHisTyrAsnSerTyrIleThrLeuSerGluTrpLeuLysIleTyr                              180185190                                                                     LysIleProCysIleGlyGlyIleAspThrArgAlaLeuThrLysLeu                              195200205                                                                     LeuArgGluLysGlySerMetLeuGlyLysIleValIleTyrLysAsn                              210215220                                                                     ArgGlnHisIleAsnLysLeuTyrLysGluIleAsnLeuPheAspPro                              225230235240                                                                  GlyAsnIleAspThrLeuLysTyrValCysAsnHisPheIleArgVal                              245250255                                                                     IleLysLeuAsnAsnIleThrTyrAsnTyrLysAsnLysGluGluPhe                              260265270                                                                     AsnTyrThrAsnGluMetIleThrAsnAspSerSerMetGluAspHis                              275280285                                                                     AspAsnGluIleAsnGlySerIleSerAsnPheAsnAsnCysProSer                              290295300                                                                     IleSerSerPheAspLysSerGluSerLysAsnValIleAsnHisThr                              305310315320                                                                  LeuLeuArgAspLysMetAsnLeuIleThrSerSerGluGluTyrLeu                              325330335                                                                     LysAspLeuHisAsnCysAsnPheSerAsnSerSerAspLysAsnAsp                              340345350                                                                     SerPhePheLysLeuTyrGlyIleCysGluTyrAspLysTyrLeuIle                              355360365                                                                     AspLeuGluGluAsnAlaSerPheHisTyrAsnAsnValAspGluTyr                              370375380                                                                     GlyTyrTyrAspValAsnLysAsnThrAsnIleLeuSerAsnAsnLys                              385390395400                                                                  IleGluGlnAsnAsnAsnAsnGluAsnAsnLysAsnAsnLysAsnAsn                              405410415                                                                     AsnAsnAsnGluValAspTyrIleLysLysAspGluAspAsnAsnVal                              420425430                                                                     AsnSerLysValPheTyrSerGlnTyrAsnAsnAsnAlaGlnAsnAsn                              435440445                                                                     GluHisThrGluPheAsnLeuAsnAsnAspTyrSerThrTyrIleArg                              450455460                                                                     LysLysMetLysAsnGluGluPheLeuAsnLeuValAsnLysArgLys                              465470475480                                                                  ValAspHisLysGluLysIleIleValIleValAspCysGlyIleLys                              485490495                                                                     AsnSerIleIleLysAsnLeuIleArgHisGlyMetAspLeuProLeu                              500505510                                                                     ThrTyrIleIleValProTyrTyrTyrAsnPheAsnHisIleAspTyr                              515520525                                                                     AspAlaValLeuLeuSerAsnGlyProGlyAspProLysLysCysAsp                              530535540                                                                     PheLeuIleLysAsnLeuLysAspSerLeuThrLysAsnLysIleIle                              545550555560                                                                  PheGlyIleCysLeuGlyAsnGlnLeuLeuGlyIleSerLeuGlyCys                              565570575                                                                     AspThrTyrLysMetLysTyrGlyAsnArgGlyValAsnGlnProVal                              580585590                                                                     IleGlnLeuValAspAsnIleCysTyrIleThrSerGlnAsnHisGly                              595600605                                                                     TyrCysLeuLysLysLysSerIleLeuLysArgLysGluLeuAlaIle                              610615620                                                                     SerTyrIleAsnAlaAsnAspLysSerIleGluGlyIleSerHisLys                              625630635640                                                                  AsnGlyArgPheTyrSerValGlnPheHisProGluGlyAsnAsnGly                              645650655                                                                     ProGluAspThrSerPheLeuPheLysAsnPheLeuLeuAspIlePhe                              660665670                                                                     AsnLysLysLysGlnTyrArgGluTyrLeuGlyTyrAsnIleIleTyr                              675680685                                                                     IleLysLysLysValLeuLeuLeuGlySerGlyGlyLeuCysIleGly                              690695700                                                                     GlnAlaGlyGluPheAspTyrSerGlyThrGlnAlaIleLysSerLeu                              705710715720                                                                  LysGluCysGlyIleTyrValIleLeuValAsnProAsnIleAlaThr                              725730735                                                                     ValGlnThrSerLysGlyLeuAlaAspLysValTyrPheLeuProVal                              740745750                                                                     AsnCysGluPheValGluLysIleIleLysLysGluLysProAspPhe                              755760765                                                                     IleLeuCysThrPheGlyGlyGlnThrAlaLeuAsnCysAlaLeuMet                              770775780                                                                     LeuAspGlnLysLysValLeuLysLysAsnAsnCysGlnCysLeuGly                              785790795800                                                                  ThrSerLeuGluSerIleArgIleThrGluAsnArgThrLeuPheAla                              805810815                                                                     GluLysLeuLysGluIleAsnGluArgIleAlaProTyrGlySerAla                              820825830                                                                     LysAsnValAsnGlnAlaIleAspIleAlaAsnLysIleGlyTyrPro                              835840845                                                                     IleLeuValArgThrThrPheSerLeuGlyGlyLeuAsnSerSerPhe                              850855860                                                                     IleAsnAsnGluGluGluLeuIleGluLysCysAsnLysIlePheLeu                              865870875880                                                                  GlnThrAspAsnGluIlePheIleAspLysSerLeuGlnGlyTrpLys                              885890895                                                                     GluIleGluTyrGluLeuLeuArgAspAsnLysAsnAsnCysIleAla                              900905910                                                                     IleCysAsnMetGluAsnIleAspProLeuGlyIleHisThrGlyAsp                              915920925                                                                     SerIleValValAlaProSerGlnThrLeuSerAsnTyrGluTyrTyr                              930935940                                                                     LysPheArgGluIleAlaLeuLysValIleThrHisLeuAsnIleIle                              945950955960                                                                  GlyGluCysAsnIleGlnPheGlyIleAsnProGlnThrGlyGluTyr                              965970975                                                                     CysIleIleGluValAsnAlaArgLeuSerArgSerSerAlaLeuAla                              980985990                                                                     SerLysAlaThrGlyTyrProLeuAlaTyrIleSerAlaLysIleAla                              99510001005                                                                   LeuGlyTyrAspLeuIleSerLeuLysAsnSerIleThrLysLysThr                              101010151020                                                                  ThrAlaCysPheGluProSerLeuAspTyrIleThrThrLysIlePro                              1025103010351040                                                              ArgTrpAspLeuAsnLysPheGluPheAlaSerAsnThrMetAsnSer                              104510501055                                                                  SerMetLysSerValGlyGluValMetSerIleGlyArgThrPheGlu                              106010651070                                                                  GluSerIleGlnLysSerLeuArgCysIleAspAspAsnTyrLeuGly                              107510801085                                                                  PheSerAsnThrTyrCysIleAspTrpAspGluLysLysIleIleGlu                              109010951100                                                                  GluLeuLysAsnProSerProLysArgIleAspAlaIleHisGlnAla                              1105111011151120                                                              PheHisLeuAsnMetProMetAspLysIleHisGluLeuThrHisIle                              112511301135                                                                  AspTyrTrpPheLeuHisLysPheTyrAsnIleTyrAsnLeuGlnAsn                              114011451150                                                                  LysLeuLysThrLeuLysLeuGluGlnLeuSerPheAsnAspLeuLys                              115511601165                                                                  TyrPheLysLysHisGlyPheSerAspLysGlnIleAlaHisTyrLeu                              117011751180                                                                  SerPheAsnThrSerAspAsnAsnAsnAsnAsnAsnAsnIleSerSer                              1185119011951200                                                              CysArgValThrGluAsnAspValMetLysTyrArgGluLysLeuGly                              120512101215                                                                  LeuPheProHisIleLysValIleAspThrLeuSerAlaGluPhePro                              122012251230                                                                  AlaLeuThrAsnTyrLeuTyrLeuThrTyrGlnGlyGlnGluHisAsp                              123512401245                                                                  ValLeuProLeuAsnMetLysArgLysLysIleCysThrLeuAsnAsn                              125012551260                                                                  LysArgAsnAlaAsnLysLysLysValHisValLysAsnHisLeuTyr                              1265127012751280                                                              AsnGluValValAspAspLysAspThrGlnLeuHisLysGluAsnAsn                              128512901295                                                                  AsnAsnAsnAsnMetAsnSerGlyAsnValGluAsnLysCysLysLeu                              130013051310                                                                  AsnLysGluSerTyrGlyTyrAsnAsnSerSerAsnCysIleAsnThr                              131513201325                                                                  AsnAsnIleAsnIleGluAsnAsnIleCysHisAspIleSerIleAsn                              133013351340                                                                  LysAsnIleLysValThrIleAsnAsnSerAsnAsnSerIleSerAsn                              1345135013551360                                                              AsnGluAsnValGluThrAsnLeuAsnCysValSerGluArgAlaGly                              136513701375                                                                  SerHisHisIleTyrGlyLysGluGluLysSerIleGlySerAspAsp                              138013851390                                                                  ThrAsnIleLeuSerAlaGlnAsnSerAsnAsnAsnPheSerCysAsn                              139514001405                                                                  AsnGluAsnMetAsnLysAlaAsnValAspValAsnValLeuGluAsn                              141014151420                                                                  AspThrLysLysArgGluAspIleAsnThrThrThrValPheMetGlu                              1425143014351440                                                              GlyGlnAsnSerValIleAsnAsnLysAsnLysGluAsnSerSerLeu                              144514501455                                                                  LeuLysGlyAspGluGluAspIleValMetValAsnLeuLysLysGlu                              146014651470                                                                  AsnAsnTyrAsnSerValIleAsnAsnValAspCysArgLysLysAsp                              147514801485                                                                  MetAspGlyLysAsnIleAsnAspGluCysLysThrTyrLysLysAsn                              149014951500                                                                  LysTyrLysAspMetGlyLeuAsnAsnAsnIleValAspGluLeuSer                              1505151015151520                                                              AsnGlyThrSerHisSerThrAsnAspHisLeuTyrLeuAspAsnPhe                              152515301535                                                                  AsnThrSerAspGluGluIleGlyAsnAsnLysAsnMetAspMetTyr                              154015451550                                                                  LeuSerLysGluLysSerIleSerAsnLysAsnProGlyAsnSerTyr                              155515601565                                                                  TyrValValAspSerValTyrAsnAsnGluTyrLysIleAsnLysMet                              157015751580                                                                  LysGluLeuIleAspAsnGluAsnLeuAsnAspGluTyrAsnAsnAsn                              1585159015951600                                                              ValAsnMetAsnCysSerAsnTyrAsnAsnAlaSerAlaPheValAsn                              160516101615                                                                  GlyLysAspArgAsnAspAsnLeuGluAsnAspCysIleGluLysAsn                              162016251630                                                                  MetAspHisThrTyrLysHisTyrAsnArgLeuAsnAsnArgArgSer                              163516401645                                                                  ThrAsnGluArgMetMetLeuMetValAsnAsnGluLysGluSerAsn                              165016551660                                                                  HisGluLysGlyHisArgArgAsnGlyLeuAsnLysLysAsnLysGlu                              1665167016751680                                                              LysAsnMetGluLysAsnLysGlyLysAsnLysAspLysLysAsnTyr                              168516901695                                                                  HisTyrValAsnHisLysArgAsnAsnGluTyrAsnSerAsnAsnIle                              170017051710                                                                  GluSerLysPheAsnAsnTyrValAspAspIleAsnLysLysGluTyr                              171517201725                                                                  TyrGluAspGluAsnAspIleTyrTyrPheThrHisSerSerGlnGly                              173017351740                                                                  AsnAsnAspAspLeuSerAsnAspAsnTyrLeuSerSerGluGluLeu                              1745175017551760                                                              AsnThrAspGluTyrAspAspAspTyrTyrTyrAspGluAspGluGlu                              176517701775                                                                  AspAspTyrAspAspAspAsnAspAspAspAspAspAspAspAspAsp                              178017851790                                                                  GlyGluAspGluGluAspAsnAspTyrTyrAsnAspAspGlyTyrAsp                              179518001805                                                                  SerTyrAsnSerLeuSerSerSerArgIleSerAspValSerSerVal                              181018151820                                                                  IleTyrSerGlyAsnGluAsnIlePheAsnGluLysTyrAsnAspIle                              1825183018351840                                                              GlyPheLysIleIleAspAsnArgAsnGluLysGluLysGluLysLys                              184518501855                                                                  LysCysPheIleValLeuGlyCysGlyCysTyrArgIleGlySerSer                              186018651870                                                                  ValGluPheAspTrpSerAlaIleHisCysValLysThrIleArgLys                              187518801885                                                                  LeuAsnHisLysAlaIleLeuIleAsnCysAsnProGluThrValSer                              189018951900                                                                  ThrAspTyrAspGluSerAspArgLeuTyrPheAspGluIleThrThr                              1905191019151920                                                              GluValIleLysPheIleTyrAsnPheGluAsnSerAsnGlyValIle                              192519301935                                                                  IleAlaPheGlyGlyGlnThrSerAsnAsnLeuValPheSerLeuTyr                              194019451950                                                                  LysAsnAsnValAsnIleLeuGlySerValHisLysValLeuIleVal                              195519601965                                                                  ValLysIleGlyIleAsnPheArgThrTyrValIleLeuLysIleAsp                              197019751980                                                                  GlnProLysTrpAsnLysPheThrLysLeuSerLysAlaIleGlnPhe                              1985199019952000                                                              AlaAsnGluValLysPheProValLeuValArgProSerTyrValLeu                              200520102015                                                                  SerGlyAlaAlaMetArgValValAsnCysPheGluGluLeuLysAsn                              202020252030                                                                  PheLeuMetLysAlaAlaIleValSerLysAspAsnProValValIle                              203520402045                                                                  SerLysPheIleGluAsnAlaLysGluIleGluIleAspCysValSer                              205020552060                                                                  LysAsnGlyLysIleIleAsnTyrAlaIleSerGluHisValGluAsn                              2065207020752080                                                              AlaGlyValHisSerGlyAspAlaThrLeuIleLeuProAlaGlnAsn                              208520902095                                                                  IleTyrValGluThrHisArgLysIleLysLysIleSerGluLysIle                              210021052110                                                                  SerLysSerLeuAsnIleSerGlyProPheAsnIleGlnPheIleCys                              211521202125                                                                  HisGlnAsnGluIleLysIleIleGluCysAsnLeuArgAlaSerArg                              213021352140                                                                  ThrPheProPheIleSerLysAlaLeuAsnLeuAsnPheIleAspLeu                              2145215021552160                                                              AlaThrArgIleLeuMetGlyTyrAspValLysProIleAsnIleSer                              216521702175                                                                  LeuIleAspLeuGluTyrThrAlaValLysAlaProIlePheSerPhe                              218021852190                                                                  AsnArgLeuHisGlySerAspCysIleLeuGlyValGluMetLysSer                              219522002205                                                                  ThrGlyGluValAlaCysPheGlyLeuAsnLysTyrGluAlaLeuLeu                              221022152220                                                                  LysSerLeuIleAlaThrGlyMetLysLeuProLysLysSerIleLeu                              2225223022352240                                                              IleSerIleLysAsnLeuAsnAsnLysLeuAlaPheGluGluProPhe                              224522502255                                                                  GlnLeuLeuPheLeuMetGlyPheThrIleTyrAlaThrGluGlyThr                              226022652270                                                                  TyrAspPheTyrSerLysPheLeuGluSerPheAsnValAsnLysGly                              227522802285                                                                  SerLysPheHisGlnArgLeuIleLysValHisAsnLysAsnAlaGlu                              229022952300                                                                  AsnIleSerProAsnThrThrAspLeuIleMetAsnHisLysValGlu                              2305231023152320                                                              MetValIleAsnIleThrAspThrLeuLysThrLysValSerSerAsn                              232523302335                                                                  GlyTyrLysIleArgArgLeuAlaSerAspPheGlnValProLeuIle                              234023452350                                                                  ThrAsnMetLysLeuCysSerLeuPheIleAspSerLeuTyrArgLys                              235523602365                                                                  PheSerArgGlnLysGluArgLysSerPheTyrThrIleLysSerTyr                              237023752380                                                                  AspGluTyrIleSerLeuVal                                                         23852390                                                                      __________________________________________________________________________

We claim:
 1. An isolated nucleic acid molecule encoding Plasmodiumfalciparum carbamoyl phosphate synthetase II, or a portion thereof,wherein the sequence of the nucleic acid molecule comprises a sequenceselected from the group consisting of nucleotides 1226 to 8401,nucleotides 1226 to 1975, nucleotides 1976 to 2671, nucleotides 2672 to3295, nucleotides 3296 to 4987, nucleotides 4988 to 6796, nucleotides6797 to 8398, nucleotides 1226 to 4585, nucleotides 3296 to 7891, andnucleotides 3296 to 8398 of SEQ. ID. NO:
 1. 2. The nucleic acid moleculeof claim 1 wherein the sequence of the nucleic acid molecule comprisesSEQ. ID. NO:
 1. 3. A vector comprising the nucleic acid of claim
 1. 4. Avector comprising the nucleic acid of claim 3.